Study of Dark Matter relic abundance in dark photon models

Author(s)

Fernanda Lima Matos

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Física (IF/SBI)
• Defense date: 2023-09-29

Examining board members

Enrico Bertuzzo; Chee Sheng Fong; Rogério Rosenfeld

• Advisor: Enrico Bertuzzo

Abstract

The fundamental nature of dark matter is one of the greatest mysteries of contemporary physics. Among the many models studied in the literature to answer this question, dark sectors are gaining more and more attention in the community. These models can reproduce the observed dark matter abundance while the feeble interactions between its components and standard model particles can explain the difficulty of obtaining direct detection signals. In this work, we study a dark sector model named the dark photon model. We investigate, through the appropriate Boltzmann equations, the impact of different mass hierarchies between this mediator and the dark matter (supposed to be a Dirac fermion) on the dark matter freeze-out. Our aim is to calculate, for different hierarchies, which values of coupling between the dark photon and the standard model are necessary to reproduce the observed dark matter relic abundance. Considering dark matter masses between 5 MeV and 1 GeV, we observed that the region in the parameter space that is viable for dark photons with masses greater than 1 GeV is small. Moreover, we obtained that the maximum value allowed for the ratio between the mass of the dark photon and the dark matter mass is slightly larger than 13. (AU)

• FAPESP's process: 20/14811-4 - Study of the abundance of light dark matter in the early universe
• Grantee: Fernanda Lima Matos
• Support Opportunities: Scholarships in Brazil - Master